The invention relates to vehicles such as golf carts or light industrial vehicles driven by direct-current electric motors, and to controls which energize such DC motors by closure of relay or solenoid contacts. More particularly, the invention relates to such DC motor controls including protective solenoid latching to prevent chatter of the solenoid contacts.
Chatter of solenoid contacts can occur, for example, during rapid vehicle accelleration or high battery load conditions when the voltage of the batteries energizing the solenoid coil drops to a level causing the solenoid to drop out or the solenoid contacts to open, thereby deenergizing the DC motor. As soon as the solenoid contacts open, however, the high battery load condition is eliminated and the voltage of the batteries increases resulting in the solenoid contacts reclosing. This opening and closing of the solenoid contacts or solenoid chatter is particularly undesirable when the voltage across the solenoid contacts exceeds an upper voltage level, since the solenoid chatter results in destruction or welding together of the solenoid contacts as a result of current arcing across the solenoid contacts.
Attention is directed to a solenoid latching switch disclosed in U.S. patent application Ser. No. 771,159, filed Feb. 23, 1977, now U.S. Pat. No. 4,099,105 and assigned to the same assignee as this application.